Customarily, in the prior art, foam core doors embody two wooden stiles, top and bottom wooden rails, and two metal skins. These elements are bonded together as an integral unit by a core of foam insulation. Some form of bottom sweep is then attached to the door by stapling, nailing or screwing into the wood bottom rail. The sweep acts as a weather seal when in contact with the frame threshold.
The present invention is an improvement on the prior art and the essence of the invention resides in the provision of a prefabricated sheet steel bottom rail with integrally molded Neoprene bottom sweep thereon, the prefabricated unit forming a bottom closure for the foam-filled door panel of increased structural integrity and efficiency.
Among the numerous advantages of the invention over the prior art are the elimination of the danger of rot at the bottom edge of the door as frequently happens where unpainted wood bottom rails are exposed to the weather; the provision of a better thermal break at the bottom of the door; elimination of ineffective fastening of the bottom sweep to the bottom rail; better positioning and squareness of the bottom rail structure; better anchorage and bonding with the urethane foam core to thereby increase the structural strength of the entire door without dependency on mastics or adhesives; a more efficient bottom sweep material by utilizing Neoprene which is less effected by temperature extremes; protection for the ungalvanized bottom edges of the metal skins which have been subject to rusting in the prior art; and easy replacement of the Neoprene bottom sweep by means of a simple unitized replacement assembly after trimming off the worn sweep flush with the bottom face of the metal bottom rail.
Some examples of the patented prior art are contained in the following U.S. patents:
U.s. pat. No. 1,877,729 PA1 U.s. pat. No. 1,949,193 PA1 U.s. pat. No. 2,592,861 PA1 U.s. pat. No. 2,686,943 PA1 U.s. pat. No. 2,949,651 PA1 U.s. pat. No. 3,024,504 PA1 U.s. pat. No. 3,068,136 PA1 U.s. pat. No. 3,334,464 PA1 U.s. pat. No. 3,518,792 PA1 U.s. pat. No. 3,762,100 PA1 U.s. pat. No. 3,796,008 PA1 U.s. pat. No. 3,834,101